Daylight developing tank

ABSTRACT

A parallelepiped daylight developing tank for developing one or more pieces of flat photographic material, such as plates or sheets of paper. The tank is formed by a body having side walls in which guideway means is provided to bear a slidable, lightproof cover provided with at least one pour-in opening and a system for stirring the solution during the developing process. The developing area of the tank is separated from its rear wall and front wall by partitions defining a system of labyrinth channels communicating with the developing area, into which the pour-in openings, provided in the cover, lead.

United States Patent 1191 Hampl Sept. 2, 1975 [54] DAYLIGHT DEVELOPING TANK 1,602,931 10/1926 Pope 354/315 3,465,664 9 1969 B0 h 354 331 [75] Inventor: Jan Hampl, Prerov, Czechoslovakia 6 man I [73] Assignee': MEOPTA,marodni podnik, Primary Examiner-Richard L. Moses Prerov, Czechoslovakia Attorney, Agent, or FirmMurray Schaffer 22 Filed: May 3, 1974 [57] 7 ABSTRACT [21] Appl' 466527 A parallelepiped daylight developing tank for developing one or more pieces of flat photographic material, [30] Forei n Ap lication Priorit Data such as plates or sheets of paper. The tank is formed g P y May 14. 1973 Czechoslovakia 3396-73 y a y having Side Walls in which guideway means is provided to bear a slidable, light-proof cover pro- 52 US. Cl. 354/312; 354/315; 354/328 vided with at least One p Opening and a system 51 1111. C1. G03d 17/00 for Stirring the Solution during the developing p [58] Field of Search 354/312, 307, 315, 32s, The developing area of the tank is separated from its 354/323, 331 rear wall and front wall by partitions defining a system of labyrinth channels communicating with the devel [56] References Cited oping area, into which the pour-in openings, provided UNITED STATES PATENTS the lead- 738,665 9/1903 Davenport 354/315 9 Claims, 6 Drawing g s PATENTED SEP 2 I975 sum 1 2 3,903,540 SEP' 21975 PATUJItD SHEET 2 of 2 DAYLIGHT DEVELOPING TANK BACKGROUND OF THE INVENTION The invention relates to a developing tank of the square or rectangle form for developing in daylight one or more pieces of the flat photographic material such as the photographic plates or papers.

Developing tanks are in common use for developing photographic material in daylight; such tanks are designed primarily for the purpose of developing striplike material of various sizes. These developing tanks comprise a vessel generallyofa cylindrical form including a lid provided with a varying system of the partition walls preventing penetration of undesired light into the developing space. Another major part of such devices is a core for positioning the strip-like photographic material, which is controlled by means of a stirrer positioned outside the magazine, to agitate the developer or the fixative bath in the course of the developing process.

With such developing tanks the photographic mate rial is inserted in the developing area in dark surroundings and only after the tank has been closed can the process be continued in daylight.

Less common are tanks for developing flat photographic materials such as the sheet film. photographic plates or the photographic paper. The aforementioned type of the developing tanks are unsuitable for such use because of the difficulty in positioning flat photographic material and since such a developing tank would serve for developing one piece only. Moreover, it is difficult to maintain the stirring of the developing solutioncontinuously in order to obtain a uniform effect of the developing solution on the sensitive layer of the photographic material. For these reasons the requirement arises to design a developing magazine in which one or more pieces of the flat, sheet-like photographic material might be easily developed-in daylight, while maintaining a simple design which is light-proof and which is provided with a simple and easily controlled stirring and deaeration system.

SUMMARY OF THE INVENTION,

According to the present invention a daylight developing tank, for photographic sheet or flat material is provided comprising a parallelpiped body having side and end walls in which partitions are used to define an interior developing area. and to define with the end walls labyrinth channels for the introduction of fluid into the developing area. A cover, slidable over the body, is provided in which inlet openings is provided for the fluid, aligned with the labyrinth channels. The cover has side walls. and they as ell as the side walls of the body are provided with cooperating means allowing the cover to slide-over the body and to engage tightly with it. The undersurface of the cover is formed to provide a fluid and light proof seal with the upper edges of the body walls. A stirring device is located in light proof manner in the cover. to agitate the fluid in the developing space.

The stirring system is formed by a plate made of the flexible material located in a recess formed in the bottom surface of the cover. The plate is attached firmly at one end to the dover and is provided with a pushbutton passing through an opening in the cover which is surrounded by a dish-like housing provided with an annulus having increased peripheral edge above the upper surface of the cover. The stirrer plate may be connected with the push butt0n by means of a pin and with a spring to increase flexibility and insure normal closing of the plate.

Each of the inner labyrinth walls may be provided with at least one finger-like clasp positioned so as to point towards the bottom of the body to grasp the sheet material. Spacing inserts are freely positioned in the developing area of the body which are made of a porous material, such as a synthetic or plastic mesh, allowing one or more sheets of photographic material to be developed at once.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 represents the tank body with the removable cover in an exploded view;

FIG. 2 is a longitudinal section through the tank body with the cover in place;

FIG. 3 is a longituidnal section through the tank showing the inserted spacing inserts and the photographic material, and a modified cover;

FIG. 4 is a view of the tank in the transverse crosssection;

FIG. 5 is a view of the tank showing a modified method of engaging the cover and body; and

FIG. 6 is a view of the tank showing still another modification of the cover and body.

As seen in FIG. 1 the developing tank in accordance with the invention consists of two major parts, i.e., a parallelepiped body I and a slidable cover 2.

The body 1 has a rectangular shape and is formed with a bottom 18 in which there are provided longitudinal projections 181 preventing the photographic material 42 being developed from adhering to the bottom 18. The outer surfaces of both of the longer sidewalls 11,12 are provided with guideways 111,121 which serve both to correctly bear and position the lid 2 and also to form a perfect light-proof seal for the de veloping space 4. Both of the shorter walls, i.e, the rear wall 13 and the front wall 14 are provided with another inner wall or partition 131 and 14 which substantially doubles their thickness and which, in combination with the cross-walls, form a system of the labyrinths 15 and 16 which act to prevent light from penetrating into the developing space 4. Between the rear wall 13 and its associated inner partition 131 a pourin space 132 is formed, while similarly, between the front wall 14 and the inner partition I41 pour-in spaces 142, 143 are formed. The front wall 14, and the inner partition 14], including the respective labyrinths 16, are of the same height, corresponding with that of both side-walls l1, 12. The inner partition 131, including the associated labyrinths 15 is ofa lower height, than that of front wall 14, while the rear wall 13 is of a still lower height, neithe r of which attaining the height of the sidewall I l. A pair of claws I9 are located on the inner partition 131, in direction towards the developing space 4, while a single claw I9 is located on the inner partition I4I directed towards the developing area 4. All of the claws I) are basically of the S shape pointing towards the bottom 18 of the body. The distance between the claws 19 on the inner partition 131 is greater than half of the width of the photographic material 42 being developed, while the claw I9 on the inner wall 14 is substantially in the center of the wall. Spacing inserts 41 made of synthetic or plastic mesh are loosely inserted in the developing space 4.

As mentioned above, and as is obvious from the FIGS. 2, 3, 4 the cover 2 is provided with grooves 221 and 231 which are drawn slidably on the guides 111 and 121. The upper wall 21 of the cover 2 is provided with the pour-in opening 213, 214, 215 located in its extreme end sections 24 and 25. The openings empty respectively in pour-in spaces 142, 143, 132 formed between the inner and outer front and rear walls. The thickness of the cover 2 is not uniform, but it is made to vary cascade-like, so that the greates thickness is in the space above the rear wall 13 and the smallest thickness is above the front wall 14. The edge 241 between the rear section 24 and the middle part 25 of the cover 2 is of the same shape as the outer surface of the inner wall 131 so that after drawing or pushing the cover 2 on to the body 1 it bears against the inner walls and seats over the entire surface. Similarly, the edge 251 between the middle part 25 and the front edge 26 of the cover 2 is formed so that its edge will bear and seat with its full surface on the inner partition 141. In this manner penetration of and undesirable disturbing light, into the developing space 4, is prevented. In the upper wall 21 of the cover 2 there is arranged a stirring system 3 formed basically by a flat flexible plate 31 placed in a corresponding slot 216 formed in the lower surface 212 of the cover. The plate 31 is fastened, with screws 32, to the bottom surface 210 of the cover 2. A pushbutton 33 is provided, which passes through an opening 27 in the cover 2, approximately in the middle of the plate 31. The top of the push button 33 extends till above the upper surface 211 of the cover2 into a cupshaped deepended part 28 provided with an increasing peripheral edge 29, extending above the surface 211.

As mentioned, the cover 2 is placed with its grooves 221 and 231 on the guideways 111 and 121 made in the side walls 11 and 12 of the body 1. Thus a perfectly light-proof connection of the cover 2 with the body 1 is assured. Moreover, this position is secured against inadvertant pushing-out of the cover by a projection 17 formed in the upper part of the front wall 14 which engages with a cut-out 217 made on the bottom surface 210 of the cover 2.

Development of rectangular photographic material in the described developing magazine is made in the following way. The cover 2 is removed from the body 1 by sliding it off. This exposes the developing space 4, in which individual sheets of photographic material 42 may then be inserted. This insertion proceeds in dark surroundings. Each sheet is separated by a spacing insert 41 to provide alternate layers of sheets and inserts. Thus perfect access of the developing solution to all of the sensitive portions of the layers is assured. Each of the sheets of the photographic material 42 is held by a spacing insert 41 in such a manner that the upper spacing insert is retained by the points 191 of the clamps 19 insuring both the correct position of the sheets in the developing space 4 and preventing their undesired movement in a direction towards the cover 2. Further more, the clamp 19 prevents the sheets from being engaged by the slidable cover, even with a large quantitity of photographic material present. After positioning the photographic material 42 to be developed and the spacing inserts 41, the cover 2 is slid onto the body 1 and is secured against being pushed out by engaging the projection 17 into the slot 217. Further process of the photographic material may thereafter be performed at the full daylight. The developing solution is poured into the pour-in spaces 142, 143 or 132 through the pour-in openings 213, 214 or 215 from which it flows into the actual developing space 4. By repeated pressure on the pushbutton 33 the plate 31 of the stirring device 3 is actuated into oscillatory or vibrating motion and the solution is effectively stirred. The occurence of the air bubbles in the emulsion being developed is prevented. In addition the solution is constantly circulated and renewed in the places of contact with the emulsion. After termination of the developing period the solution is drained via the pour-in holes213, 214 or 215 and it is replaced by another solution necessary for the further process of developing and fixating.

The above mentioned construction of the developing tank is not the only possible solution within the concept of the present invention. Further design modifications are possible, which, for example, may consist, first of all, in differing variations in the form of labyrinth, and in a differing system of drawing the cover on the body 1, as shown for example in FIGS. 5 and 6. According to FIG. 5, the cover 2 is positioned in such a manner that grooves 221, 231 may be formed in the side walls '11-, 12 while the cover 2 is provided with the corresponding guideway 111, 121, 121. Similar solution is shown in FIG. 6 with the difference that the guideway 111, 121 and the grooves 221, 231 are separable also in the direction perpendicular to the bottom 18 of the body 1 while in the preceding case is was separable only in the direction parallel to the bottom 18.

Further design variations are possible with the stirring device. According to FIG. 3 the plate 31 is connected with the pushbutton 33 by a pin 34 bearing a helical spring 35. As a result, a more reliable elasticity of the plate 31 is achieved.

Moreover, the light-proofing of the pushbutton 33 may be solved in other ways, as well as the gripping of the photographic material, and the spacing inserts 42 in the developing space 4. In principle, however, it is necessary to ensure perfect light-proofing of the tank by one system of the labyrinths at and by a correspondingly modified lid and, in addition, to provide the tank with a stirring device based on the above principle.

The present tank guarantees a perfect developing of one or more pieces of the flat photographic materials and it is, therefore, especially suited for mass developing process. It may serve not only for the amateur purposes, but for the professional ones as well as when such a mass developing process means substantial savings of the developing time.

I claim:

1. A photographic developing tank comprising a parallelepiped body having side and end walls, a pair of interior partitions extending between said side walls spaced from each other to define a developing area within said body and spaced respectively from each of the end walls to define labyrinth channels at each end of said body communicating with said developing area, a removable cover for said body, having openings aligned with said labyrinth channels for introduction and removal of fluid, said cover and said body having cooperating means for maintaining said developing area light-free, and a systemfor stirring, comprising an elongated, flexible plate secured at one end to the lower surface of said cover and having its other end extending over said developing area, an actuating button in contact with said plate, said aeuating button passing through a hole in said cover, said hole being surrounded by an annular flange forming a disk shaped recess for said button.

2. The developing tank according to claim 1 wherein the lower surface of said cover is formed with a recess for normally receiving said flexible plate.

3. The developing tank according to claim 1 wherein said button is attached to said plate. and including spring means for normally biasing said button outwardly of said plate 4. The developing tank according to claim 3 including a pin connecting said button on said plate and a helical spring surrounding said button between said cover and said button.

5. The developing tank according to claim 1 including spacers loosely inserted within said developing area for supporting photographic sheets to be developed, said spacers comprising a plastic mesh body adapted to permit circulation of fluid within said area.

6. The developing tank according to claim 1 including means mounted on said partitions and extending into said developing area for grasping photographic sheets located in said developing area.

7. The developing tank according to claim 1 wherein said grasping means comprise at least one resilient claw mounted on the upper edge of said partion and extending toward the bottom of said body.

8. A photographic developing tank comprising a parallelepiped body having side and end walls, interior partitions extending between said side walls spaced from each other to define a developing area within said body and spaced respectively from each of the end walls to define labyrinth channels at each end of said body communicating with said developing area, and a cover for enclosing said body having openings aligned with said labyrinth channels for the introduction and removal of fluid, said cover having side walls adapted to depend adjacent the sidewalls of said body, and to be slidable over said body from one end to the other, said side walls of said body and cover having cooperating means for slidably engaging said body in closed condition, the lower surface of said cover having means engaging the upper edges of said side and end walls and said partitions to seal said body against passage of fluid and light.

9. The developing tank according to claim 8 wherein the upper edge of the side and end walls of said body and said partition vary in height from one end to the other, and said cover varies in thickness corresponding thereto. 

1. A photographic developing tank comprising a parallelepiped body having side and end walls, a pair of interior partitions extending between said side walls spaced from each other to define a developing area within said body and spaced respectively from each of the end walls to define labyrinth channels at each end of said body communicating with said developing area, a removable cover for said body, having openings aligned with said labyrinth channels for introduction and removal of fluid, said cover and said body having cooperating means for maintaining said developing area light-free, and a system for stirring, comprising an elongated, flexible plate secured at one end to the lower surface of said cover and having its other end extending over said developing area, an actuating button in contact with said plate, said acuating button passing through a hole in said cover, said hole being surrounded by an annular flange forming a disk shaped recess for said button.
 2. The developing tank according to claim 1 wherein the lower surface of said cover is formed with a recess for normally receiving said flexible plate.
 3. The developing tank according to claim 1 wherein said button is attached to said plate, and including spring means for normally biasing said button outwardly of said plate.
 4. The developing tank according to claim 3 including a pin connecting said button on said plate and a helical spring surrounding said button between said cover and said button.
 5. The developing tank according to claim 1 including spacers loosely inserted within said developing area for supporting photographic sheets to be developed, said spacers comprising a plastic mesh body adapted to permit circulation of fluid within said area.
 6. The developing tank according to claim 1 including means mounted on said partitions and extending into said developing area for grasping photographic sheets located in said developing area.
 7. The developing tank according to claim 1 wherein said grasping means comprise at least one resilient claw mounted on the upper edge of said partion and extending toward the bottom of said body.
 8. A photographic developing tank comprising a parallelepiped body having side and end walls, interior partitions extending between said side walls spaced from each other to define a developing area within said body and spaced respectively from each of the end walls to define labyrinth channels at each end of said body communicating with said developing area, and a cover for enclosing said body having openings aligned with said labyrinth channels for the introduction and removal of fluid, said cover having side walls adapted to depend adjacent the sidewalls of said body, and to be slidable over said body from one end to the other, said side walls of said body and cover having cooperating means for slidably engaging said body in closed condition, the lower surface of said cover having means engaging the upper edges of said side and end walls and said partitions to seal said body against passage of fluid and light.
 9. The developing tank according to claim 8 wherein the upper edge of the side and end walls of said body and said partition vary in height from one end to the other, and said cover varies in thickness corresponding thereto. 